Koko, the gorilla who mastered sign language, has died.

The Gorilla Foundation says the 46-year-old western lowland gorilla died in her sleep at the foundation鈥檚 preserve in California鈥檚 Santa Cruz mountains on Tuesday.

https://twitter.com/AnimalPlanet/status/1009833342798389248

Koko was born at the San Francisco Zoo, and Dr. Francine Patterson began teaching the gorilla sign language that became part of a Stanford University project in 1974.

The foundation says Koko鈥檚 capacity for language and empathy opened the minds and hearts of millions.

Koko appeared in many documentaries and twice in National Geographic. The gorilla鈥檚 1978 cover featured a photo that the animal had taken of herself in a mirror.

The foundation says it will honour Koko鈥檚 legacy with a sign language application featuring Koko for the benefit of gorillas and children, as well as other projects.

The Associated Press

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